package tcp_server;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class TcpEchoServer {
    private ServerSocket serverSocket = null;

    public TcpEchoServer(int port) throws IOException {
        serverSocket = new ServerSocket(port);
    }

    public void start() throws IOException {
        System.out.println("服务器启动!");
        ExecutorService pool = Executors.newCachedThreadPool();
        while (true){
            Socket clientSocket = serverSocket.accept();
//            Thread t = new Thread(()->{
//                processConnection(clientSocket);
//            });
//            t.start();

            pool.submit(new Runnable() {
                @Override
                public void run() {
                    processConnection(clientSocket);
                }
            });
        }
    }

    //通过这个方法处理一次连接,连接建立的过程中就会涉及到多次的请求响应交互
    private void processConnection(Socket clientSocket) {
        System.out.printf("[%s:%d] 客户端上线!\n",clientSocket.getInetAddress(),clientSocket.getPort());
        //循环的读取客户端的请求并返回响应
        try (InputStream inputStream = clientSocket.getInputStream();
             OutputStream outputStream = clientSocket.getOutputStream()) {
            Scanner scanner = new Scanner(inputStream);
            while (true){
                if (!scanner.hasNext()){
                    System.out.printf("[%s:%d] 客户端下线!\n",clientSocket.getInetAddress(),clientSocket.getPort());
                    break;
                }
                String request = scanner.next();
                String reponse = process(request);
//                outputStream.write(reponse.getBytes(),0,reponse.getBytes().length);
                PrintWriter printWriter = new PrintWriter(outputStream);
                printWriter.println(reponse);
                printWriter.flush();

                System.out.printf("[%s:%d] req: %s, resp: %s\n", clientSocket.getInetAddress(),
                        clientSocket.getPort(),request,reponse);
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public String process(String request) {
        return request;
    }

    public static void main(String[] args) throws IOException {
        TcpEchoServer server = new TcpEchoServer(9090);
        server.start();
    }
}
